scholarly journals The Effect of Salmon Food-Derived DOM and Glacial Melting on Activity and Diversity of Free-Living Bacterioplankton in Chilean Patagonian Fjords

2022 ◽  
Vol 12 ◽  
Author(s):  
Paulina Montero ◽  
Marcelo H. Gutiérrez ◽  
Giovanni Daneri ◽  
Bárbara Jacob
Keyword(s):  
Organic Matter ◽  
Community Diversity ◽  
Organic Enrichment ◽  
Phytoplankton Production ◽  
Organic Substrates ◽  
Free Living ◽  
Autochthonous Organic Matter ◽  
Southern Patagonia ◽  
Glacial Melting ◽  
Patagonian Fjords

Fjord ecosystems cycle and export significant amounts of carbon and appear to be extremely sensitive to climate change and anthropogenic perturbations. To identify patterns of microbial responses to ongoing natural and human-derived changes in the fjords of Chilean Patagonia, we examined the effect of organic enrichment associated with salmon aquaculture and freshening produced by glacial melting on bacterial production (BP), extracellular enzymatic activity (EEA), and community diversity of free-living bacterioplankton. We assayed the effects of salmon food-derived dissolved organic matter (SF-DOM) and meltwaters through microcosm experiments containing waters from Puyuhuapi Fjord and the proglacial fjords of the Southern Patagonia Icefield, respectively. Rates of BP and EEA were 2 times higher in the presence of SF-DOM than in controls, whereas the addition of autochthonous organic matter derived from diatoms (D-DOM) resulted in rates of BP and EEA similar to those measured in the controls. The addition of SF-DOM also reduced species richness and abundance of a significant fraction of the representative taxa of bacterioplankton of Puyuhuapi Fjord. In the proglacial fjords, bacterioplankton diversity was reduced in areas more heavily influenced by meltwaters and was accompanied by moderate positive changes in BP and EEA. Our findings strongly suggest that SF-DOM is highly reactive, promoting enhanced rates of microbial activity while could be influencing the diversity of bacterioplankton communities in Patagonian fjords with a strong salmon farming activity. These findings challenge the traditional view of phytoplankton production as the primary source of labile DOM that fuels heterotrophic activity in coastal ecosystems impacted by anthropogenic organic enrichment. Given the intensive local production of salmon, we analyze the significance of this emerging source of rich “allochthonous” organic substrates for autotrophic/heterotrophic balance, carbon exportation, and hypoxia in Patagonian fjords. The effect of human DOM enrichment can be enhanced in proglacial fjords, where progressive glacial melting exerts additional selective pressure on bacterioplankton diversity.

scholarly journals Nutrient behavior in a highly-eutrophicated tropical estuarine system

2016 ◽  
Vol 28 (0) ◽  
Author(s):  
Nilva Brandini ◽  
◽  
Ana Paula de Castro Rodrigues ◽  
Ilene Matanó Abreu ◽  
Luiz Carlos Cotovicz Junior ◽  
...  
Keyword(s):  
Organic Matter ◽  
Chlorophyll A ◽  
River Mouth ◽  
Nutrient Concentrations ◽  
Phytoplankton Production ◽  
Small Scale ◽  
Estuarine System ◽  
Temperature Conductivity ◽  
Se Brazil ◽  
Iguaçu River

Abstract Aim: There are few studies dealing with the biogeochemical processes occurring in small estuaries receiving high sewage loading in tropical regions. The aim of this investigation was to characterize the biogeochemical behavior of nutrients in superficial waters collected at the Iguaçu estuarine system, during specific conditions (neap tide), located at the inner sector of a heavily eutrophicated embayment (Guanabara Bay, SE Brazil). Methods Physical and chemical variables were measured in situ (pH, temperature, conductivity, salinity, total dissolved solids, transparency, dissolved oxygen), whereas suspended particulate matter, chlorophyll a, phaepigments and nutrients (carbon, nitrogen and phosphorus forms) were measured in laboratory across the mesohaline estuarine gradient. Results The Iguaçu River mouth is in a high stage of eutrophication, considering nutrient concentrations, chlorophyll a and transparency of water column. Results indicate a transition from heterotrophic conditions to autotrophic conditions, since the nutrients concentrations showed a decreasing pattern along the saline gradient, while the chlorophyll an increased over the transects. The pH values and chlorophyll : phaeopigments ratios are significantly related to the amount and quality of organic matter contents, especially at transects under strong marine influence. More than 95% of the dissolved and total nitrogen concentrations are represented by NH4+ contributions, which are related to the ammonification of organic matter contents in this region, indicating the existence of untreated sewage loads in this area. Conclusion In this study, the Iguaçu River seemed to contribute with high inputs of nutrients that support important phytoplankton production at the inner regions of the bay related to the CO2 sink and autotrophic metabolism, showing the importance of verifying the biogeochemical behaviors of nutrients in estuarine areas, even in small scale.

Isotopic fingerprints on lacustrine organic matter from Laguna Potrok Aike (southern Patagonia, Argentina) reflect environmental changes during the last 16,000 years

2008 ◽  
Vol 42 (1) ◽  
pp. 81-102 ◽  
Author(s):  
Christoph Mayr ◽  
Andreas Lücke ◽  
Nora I. Maidana ◽  
Michael Wille ◽  
Torsten Haberzettl ◽  
...  
Keyword(s):  
Organic Matter ◽  
Environmental Changes ◽  
Southern Patagonia

scholarly journals The Biodegradation of Soil Organic Matter in Soil-Dwelling Humivorous Fauna

2022 ◽  
Vol 9 ◽  
Author(s):  
Xuliang Lou ◽  
Jianming Zhao ◽  
Xiangyang Lou ◽  
Xiejiang Xia ◽  
Yilu Feng ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Substrates ◽  
Terrestrial Organic Matter ◽  
Symbiotic Associations ◽  
Tropical Areas ◽  
Gut Symbionts ◽  
Diverse Community ◽  
Ecological Success ◽  
Global Vegetation

Soil organic matter contains more carbon than global vegetation and the atmosphere combined. Gaining access to this source of organic carbon is challenging and requires at least partial removal of polyphenolic and/or soil mineral protections, followed by subsequent enzymatic or chemical cleavage of diverse plant polysaccharides. Soil-feeding animals make significant contributions to the recycling of terrestrial organic matter. Some humivorous earthworms, beetles, and termites, among others, have evolved the ability to mineralize recalcitrant soil organic matter, thereby leading to their tremendous ecological success in the (sub)tropical areas. This ability largely relies on their symbiotic associations with a diverse community of gut microbes. Recent integrative omics studies, including genomics, metagenomics, and proteomics, provide deeper insights into the functions of gut symbionts. In reviewing this literature, we emphasized that understanding how these soil-feeding fauna catabolize soil organic substrates not only reveals the key microbes in the intestinal processes but also uncovers the potential novel enzymes with considerable biotechnological interests.

scholarly journals Αλλαγές στις θαλάσσιες βακτηριακές κοινότητες σε συνθήκες εμπλουτισμού με θρεπτικά

2014 ◽  
Author(s):  
Στυλιανός Φοδελιανάκης
Keyword(s):  
Organic Matter ◽  
Water Column ◽  
Nutrient Enrichment ◽  
Eastern Mediterranean ◽  
Community Diversity ◽  
Coastal Sediment ◽  
Common Source ◽  
Composition And Structure ◽  
Taxonomic Groups ◽  
Bacterioplankton Communities

Nutrient enrichment is a common source of disturbance for marineecosystems. A prerequisite for the prediction of the effects of nutrient enrichment atthe ecosystem level is the understanding of the ecological mechanisms governingbacterioplankton communities, due to their high affinity with nutrients. The aim ofthis thesis was to examine changes in the composition and structure ofbacterioplankton communities of the water column and coastal sediment undernutrient enrichment. Three studies were conducted for that purpose: two in closedexperimental conditions and one examining changes in situ. In the first two studies,changes in the water column bacterioplankton communities were examined after Paddition and in nutrient enriched habitats, respectively. In the third study, changes inthe communities of coastal sediment were examined with and without the additionof organic matter and aeration of the water column. The main conclusions from theresults of this thesis were:a) Bacterioplankton communities of the Eastern Mediterranean show a high degreeof resistance to short-term P addition, although their biomass and production islimited by P.b) Five abundant taxonomic groups showed a similar pattern of change across threedifferent nutrient enriched habitats. These groups could be potentially used asindicators for monitoring nutrient enrichment at the water column.c) After incubation under presence or absence of organic enrichment, sedimentbacterial communities originating from different habitats clustered based on theincubation conditions rather than on the area of origin. That occurred faster for twoout of the three areas, where the amount of organic matter in the sediment wasinitially higher and bacterial community diversity was lower. These results indirectlysupport the theory of Baas-Becking that "everything is everywhere but theenvironment selects" and the positive correlation between diversity and communitystability.

scholarly journals Effect of elevated CO<sub>2</sub> on the dynamics of particle attached and free living bacterioplankton communities in an Arctic fjord

2012 ◽  
Vol 9 (8) ◽  
pp. 10725-10755 ◽  
Author(s):  
M. Sperling ◽  
J. Piontek ◽  
G. Gerdts ◽  
A. Wichels ◽  
H. Schunck ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Atmospheric Carbon Dioxide ◽  
Intergenic Spacer ◽  
Extracellular Enzyme ◽  
The Arctic ◽  
Organic Substrates ◽  
Viral Lysis ◽  
Free Living ◽  
High Co2 ◽  
Carbon Dioxide Co2

Abstract. The increase in atmospheric carbon dioxide (CO2) results in acidification of the oceans, expected to lead to the fastest drop in ocean pH in the last 300 million years, if anthropogenic emissions are continued at present rate. Due to higher solubility of gases in cold waters and increased exposure to the atmosphere by decreasing ice cover, the Arctic Ocean will be among the areas most strongly affected by ocean acidification. Yet, the response of the plankton community of high latitudes to ocean acidification has not been studied so far. This work is part of the Arctic campaign of the European Project on Ocean Acidification (EPOCA) in 2010, employing 9 in situ mesocosms of about 45 000 l each to simulate ocean acidification in Kongsfjorden, Svalbard (78°56.2' N 11°53.6' E). In the present study, we investigated effects of elevated CO2 on the composition and richness of particle attached (PA; >3 μm) and free living (FL; <3 μm >0.2 μm) bacterial communities by Automated Ribosomal Intergenic Spacer Analysis (ARISA) in 6 of the mesocosms and the surrounding fjord, ranging from 185 to 1050 initial μatm pCO2. ARISA was able to resolve about 20–30 bacterial band-classes per sample and allowed for a detailed investigation of the explicit richness. Both, the PA and the FL bacterioplankton community exhibited a strong temporal development, which was driven mainly by temperature and phytoplankton development. In response to the breakdown of a picophytoplankton bloom (phase 3 of the experiment), number of ARISA-band classes in the PA-community were reduced at low and medium CO2 (∼180–600 μatm) by about 25%, while it was more or less stable at high CO2 (∼ 650–800 μatm). We hypothesise that enhanced viral lysis and enhanced availability of organic substrates at high CO2 resulted in a more diverse PA-bacterial community in the post-bloom phase. Despite lower cell numbers and extracellular enzyme activities in the post-bloom phase, bacterial protein production was enhanced in high CO2-treatments, suggesting a positive effect of community richness on this function and on carbon cycling by bacteria.

Some aspects of pollution in Southampton Water

1972 ◽  
Vol 180 (1061) ◽  
pp. 451-468 ◽  
Keyword(s):  
Organic Matter ◽  
Total Mercury ◽  
Mercenaria Mercenaria ◽  
Dry Mass ◽  
High Rate ◽  
Organic Substrates ◽  
Southampton Water ◽  
Thermal Changes ◽  
Particulate Iron ◽  
Phosphate Nitrate

The levels of some trace metals have been studied in Southampton Water. Particulate iron, though variable, is generally high and the concentration appears to be correlated with the amount of particulate matter. Zinc is approximately doubled in concentration inside Southampton Water, but much higher levels are occasionally encountered. Copper and nickel are only somewhat higher and total mercury is lower inside Southampton Water than in Solent waters. Zinc and copper are concentrated approximately 30000 times on a dry mass basis by Mercenaria mercenaria . Mercury is concentrated by Mercenaria and other bivalves; the mud which is especially rich in total mercury may represent an important source of mercury for these animals. Primary nutrients, phosphate, nitrate and ammonium, increase in concentration from seaward on proceeding up the estuεry. Surface waters appear to be especially rich in nitrate and ammonium. Gross pollution seems unlikely in view of low nitrite concentration and high oxygen values virtually throughout the estuary. The high rate of turnover of organic substrates by heterotrophic organisms may be associated with relatively large amounts of organic matter in Southampton Water. This has to some extent been confirmed by direct surveys of particulate and dissolved organic carbon which also suggest that regional differences exist. Higher levels of organic matter occur near the head of the estuary, near Marchwood, the Docks, and the mouth of the River Itchen. Although thermal changes in Southampton Water appear to have been slight, some increase in winter minimal temperatures and in summer maxima have occurred, especially in the Marchwood area. No evidence exists of deleterious effects on marine organisms. Phytoplankton can apparently endure rises of at least 10°C for short periods without injurious effects. The density of zooplankton has not decreased; possibly certain species (e. g. Elminius modestus ) have been favoured by thermal changes. A marked increase in Mercenaria mercenaria population may be associated with the small thermal rise and remarkably high population densities are encountered. Spawning appears to be correlated with summer temperatures exceeding 18 to 19°C.

Dissolved organic matter as P source for biofilms in two contrasting low-order streams

2019 ◽  
Vol 193 (2) ◽  
pp. 131-142
Author(s):  
Verónica Díaz-Villanueva
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Deciduous Forest ◽  
Spatial Scales ◽  
Algal Species ◽  
Community Level ◽  
Nutrient Concentrations ◽  
Organic Substrates ◽  
One Year ◽  
Forest Streams

Forest streams receive large amounts of leaves whose leachates are an important source of dissolved organic matter (DOM), providing not only carbon but also organic nutrients to the microbial communities in streams. I carried out a field study to evaluate the effect of different DOM concentrations on the biofilm structure and functional traits in two similar forest streams belonging to the same catchment. I compared biofilm biomass and nutri- ent content throughout one year, algal species composition, and biofilm community-level physiological profiles in two streams with different DOM concentration and aromaticity. Dissolved nutrient concentrations were higher in the stream with higher DOM concentration, with a concomitant higher biofilm biomass, and there was also a temporal pattern, with higher values during the autumn. Phosphorus content in biofilms was also higher in the high DOM stream, coincidently with a higher capacity of the community to utilize organic P source (glucose-1-P) as a substrate. In contrast, the biofilms from the stream with lower DOM concentrations preferentially used N-organic substrates (amino acids and amines). These results reveal that the biofilms of forest streams make use of organic matter nutrients, so that streams with different DOM loads may differ in biofilm biomass due to changes in both bacterial and autotrophic biomass. In addition, biofilm dynamics may be related to forest phenology, as the highest OM input in this deciduous forest is represented by tree leaves, which supply DOM through leachates, and in particular, with P-rich leachates. In conclusion, different DOM concentrations in two nearby streams led to differences in the community-level physiological profile, as has been previously demonstrated at larger spatial scales in oceans, lakes and along larger rivers.

scholarly journals Organic sediment formed during inundation of a degraded fen grassland emits large fluxes of CH<sub>4</sub> and CO<sub>2</sub>

2011 ◽  
Vol 8 (6) ◽  
pp. 1539-1550 ◽  
Author(s):  
M. Hahn-Schöfl ◽  
D. Zak ◽  
M. Minke ◽  
J. Gelbrecht ◽  
J. Augustin ◽  
...  
Keyword(s):  
Organic Matter ◽  
Plant Litter ◽  
Electron Acceptors ◽  
Sediment Layer ◽  
Organic Substrates ◽  
Peat Layer ◽  
Ch4 Production ◽  
Fresh Plant ◽  
Fresh Organic Matter ◽  
Organic Sediment

Abstract. Peatland restoration by inundation of drained areas can alter local greenhouse gas emissions as CO2 and CH4. Factors that can influence these emissions include the quality and amount of substrates available for anaerobic degradation processes and the sources and availability of electron acceptors. In order to learn about possible sources of high CO2 and CH4. emissions from a rewetted degraded fen grassland, we performed incubation experiments that tested the effects of fresh plant litter in the flooded peats on pore water chemistry and CO2 and CH4. production and emission. The position in the soil profile of the pre-existing drained peat substrate affected initial rates of anaerobic CO2 production subsequent to flooding, with the uppermost peat layer producing the greatest specific rates of CO2 evolution. CH4 production rates depended on the availability of electron acceptors and was significant only when sulfate concentrations were reduced in the pore waters. Very high specific rates of both CO2 (maximum of 412 mg C d−1 kg−1 C) and CH4 production (788 mg C d−1 kg−1 C) were observed in a new sediment layer that accumulated over the 2.5 years since the site was flooded. This new sediment layer was characterized by overall low C content, but represented a mixture of sand and relatively easily decomposable plant litter from reed canary grass killed by flooding. Samples that excluded this new sediment layer but included intact roots remaining from flooded grasses had specific rates of CO2 (max. 28 mg C d−1 kg−1 C) and CH4 (max. 34 mg C d−1 kg−1 C) production that were 10–20 times lower than for the new sediment layer and were comparable to those of a newly flooded upper peat layer. Lowest rates of anaerobic CO2 and CH4 production (range of 4–8 mg C d−1 kg−1 C and <1 mg C d−1 kg−1 C) were observed when all fresh organic matter sources (plant litter and roots) were excluded. In conclusion, the presence of fresh organic substrates such as plant and root litter originating from plants killed by inundation has a high potential for CH4 production, whereas peat without any fresh plant-derived material is relatively inert. Significant anaerobic CO2 and CH4 production in peat only occurs when some labile organic matter is available, e.g. from remaining roots or root exudates.

Dissimilar bacterial and fungal decomposer communities across rich to poor fen peatlands exhibit functional redundancy

2015 ◽  
Vol 95 (3) ◽  
pp. 219-230 ◽  
Author(s):  
Kristine M. Haynes ◽  
Michael D. Preston ◽  
James W. McLaughlin ◽  
Kara Webster ◽  
Nathan Basiliko
Keyword(s):  
Organic Matter ◽  
Microbial Communities ◽  
Environmental Changes ◽  
Functional Redundancy ◽  
Organic Substrates ◽  
Metabolic Potential ◽  
Vegetation Communities ◽  
Chemical Complexity ◽  
Poor Fen

Haynes, K. M., Preston, M. D., McLaughlin, J. W., Webster, K. and Basiliko, N. 2015. Dissimilar bacterial and fungal decomposer communities across rich to poor fen peatlands exhibit functional redundancy. Can. J. Soil Sci. 95: 219–230. Climatic and environmental changes can lead to shifts in the dominant vegetation communities present in northern peatland ecosystems, including from Sphagnum- to vascular-dominated systems. Such shifts in vegetation result in changes to the chemical quality of carbon substrates for soil microbial decomposers, with leaves and roots deposited in the peat surface and subsurface that potentially decompose faster. This study characterized the bacterial and fungal communities present along a nutrient gradient ranging from rich to poor fen peatlands and assessed the metabolic potential of these communities to mineralize a variety of organic matter substrates of varying chemical complexity using substrate-induced respiration (SIR) assays. Distinct microbial communities existed between rich, intermediate and poor fens, but SIR in each of the three sites exhibited the same pattern of carbon mineralization, providing support for the concept of functional redundancy, at least under standardized in vitro conditions. Preferential mineralization of simple organic substrates in the rich fen and complex compounds in the poor fen was not observed. Similarly, no preference was given to “native” organic matter extracts derived from each fen, with microbial communities opting for the most bioavailable substrate. This study suggests that soil bacteria and fungi might be able to respond relatively rapidly to shifts in vegetation communities and subsequent changes in the quality of carbon substrate additions to peatlands associated with environmental and climatic change.

scholarly journals Organo-Mineral Interactions Are More Important for Organic Matter Retention in Subsoil Than Topsoil

Soil Systems ◽  
2020 ◽  
Vol 4 (1) ◽  
pp. 4 ◽  
Author(s):  
Vincent Poirier ◽  
Isabelle Basile-Doelsch ◽  
Jérôme Balesdent ◽  
Daniel Borschneck ◽  
Joann K. Whalen ◽  
...  
Keyword(s):  
Organic Matter ◽  
Crop Residue ◽  
Crop Residues ◽  
Clay Content ◽  
X Ray Diffraction ◽  
Density Fractions ◽  
Organic Matter Concentration ◽  
Fractionation Procedure ◽  
Autochthonous Organic Matter ◽  
C And N

Decomposing crop residues contribute to soil organic matter (SOM) accrual; however, the factors driving the fate of carbon (C) and nitrogen (N) in soil fractions are still largely unknown, especially the influence of soil mineralogy and autochthonous organic matter concentration. The objectives of this work were (1) to evaluate the retention of C and N from crop residue in the form of occluded and mineral-associated SOM in topsoil (0–20 cm) and subsoil (30–70 cm) previously incubated for 51 days with 13C-15N-labelled corn residues, and (2) to explore if specific minerals preferentially control the retention of residue-derived C and N in topsoil and subsoil. We used topsoil and subsoil having similar texture and mineralogy as proxies for soils being rich (i.e., topsoil) and poor (i.e., subsoil) in autochthonous organic matter. We performed a sequential density fractionation procedure and measured residue-derived C and N in occluded and mineral-associated SOM fractions, and used X-ray diffraction analysis of soil density fractions to investigate their mineralogy. In accordance with our hypothesis, the retention of C and N from crop residue through organo-mineral interactions was greater in subsoil than topsoil. The same minerals were involved in the retention of residue-derived organic matter in topsoil and subsoil, but the residue-derived organic matter was associated with a denser fraction in the subsoil (i.e., 2.5–2.6 g cm−3) than in the topsoil (i.e., 2.3–2.5 g cm−3). In soils and soil horizons with high clay content and reactive minerals, we find that a low SOM concentration leads to the rapid stabilization of C and N from newly added crop residues.

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